Department of Medicine, University of California, San Francisco, CA, USA.
Osteoporos Int. 2010 Mar;21(3):439-45. doi: 10.1007/s00198-009-0974-2. Epub 2009 Jun 9.
To determine the laboratory reproducibility of urine N-telopeptide and serum bone-specific alkaline phosphatase measurements, we sent identical specimens to six US commercial labs over an 8-month period. Longitudinal and within-run laboratory reproducibility varied substantially. Efforts to improve the reproducibility of these tests are needed.
We assessed the laboratory reproducibility of urine N-telopeptide (NTX) and serum bone-specific alkaline phosphatase (BAP).
Serum and urine were collected from five postmenopausal women, pooled, divided into identical aliquots, and frozen. To evaluate longitudinal reproducibility, identical specimens were sent to six US commercial labs on five dates over an 8-month period. To evaluate within-run reproducibility, on the fifth date, each lab was sent five identical specimens. Labs were unaware of the investigation.
Longitudinal coefficients of variation (CVs) ranged from 5.4% to 37.6% for NTX and from 3.1% to 23.6% for BAP. Within-run CVs ranged from 1.5% to 17.2% for NTX. Compared to the Osteomark NTX assay, the Vitros ECi NTX assay had significantly higher longitudinal reproducibility (mean CV 7.2% vs. 30.3%, p < 0.0005) and within-run reproducibility (mean CV 3.5% vs. 12.7%, p < 0.0005).
Reproducibility of urine NTX and serum BAP varies substantially across US labs.
为了确定尿 N-端肽和血清骨特异性碱性磷酸酶测量的实验室重现性，我们在 8 个月的时间内将相同的标本送到 6 个美国商业实验室。纵向和实验室内部重复性变化很大。需要努力提高这些测试的重现性。
我们评估了尿 N-端肽（NTX）和血清骨特异性碱性磷酸酶（BAP）的实验室重现性。
从 5 名绝经后妇女收集血清和尿液，混合，分成相同的等分试样，并冷冻。为了评估纵向重复性，在 8 个月的时间内，将相同的标本分 5 批送到 6 个美国商业实验室。为了评估实验室内部重复性，在第 5 天，每个实验室都收到了 5 个相同的标本。实验室不知道这项调查。
纵向变异系数（CV）范围为 5.4%至 37.6%的 NTX 和 3.1%至 23.6%的 BAP。NTX 的实验室内部 CV 范围为 1.5%至 17.2%。与 Osteomark NTX 测定相比，Vitros ECi NTX 测定具有更高的纵向重复性（平均 CV 7.2%对 30.3%，p<0.0005）和实验室内部重复性（平均 CV 3.5%对 12.7%，p<0.0005）。
美国各实验室之间尿 NTX 和血清 BAP 的重现性差异很大。
